ios8 使用storyboard 进行自动布局

e

常见符号  

H:

水平布局（默认）

V:

垂直布局

|

superView的边界,水平布局模式下,放在左边是左边界，放在右边是右边界；处置布局模式下，则相应的为上边界和下边界

-　

标准间隔距离

-N-

长度为N像素点的间隔距离

[view]

被约束的view

==，>=，<=

用于限制view的长宽

@N

约束生效的优先级，最高是1000，等级高的优先考虑

例如：

    [NSLayoutConstraint constraintsWithVisualFormat:@"|-50-[redView(==100)]-30-[blueView(==100)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(redView,blueView)];

其中，@"|-50-[redView(==100)]-30-[blueView(==100)]"的意思理解为：redView宽度为100，距离superView的左边界为50，与blueView的间距始终保持30，blueView的宽度为100

[objc] view plaincopy

1. - (void)viewDidLoad {  
2.     [super viewDidLoad];  
3.     self.view.backgroundColor = [UIColor whiteColor];  
4.     // 1 创建三个视图 红/绿/蓝/黄/橙色视图  
5.       
6.     // 红  
7.     UIView *redView = [self alive];  
8.     redView.backgroundColor = [UIColor redColor];  
9.     [self.view addSubview:redView];  
10.     // 绿  
11.     UIView *greenView = [self alive];  
12.     greenView.backgroundColor = [UIColor greenColor];  
13.     [self.view addSubview:greenView];  
14.     // 蓝  
15.     UIView *blueView = [self alive];  
16.     blueView.backgroundColor = [UIColor blueColor];  
17.     [self.view addSubview:blueView];  
18.     // 黄  
19.     UIView *yellowView = [self alive];  
20.     yellowView.backgroundColor = [UIColor yellowColor];  
21.     [self.view addSubview:yellowView];  
22.     // 橙  
23.     UIView *orangeView = [self alive];  
24.     orangeView.backgroundColor = [UIColor orangeColor];  
25.     [self.view addSubview:orangeView];  
26.       
27.     [self.view addConstraints:[self portraitConstraints:redView :greenView :blueView yellowView:yellowView orangeView:orangeView]];  
28.       
29. }  
30. // 这样写完全是为了代码的方便使用,创建对象的同时初始化控件  
31. - (UIView *)alive  
32. {  
33.     UIView *newView = [UIView new];  
34.     newView.translatesAutoresizingMaskIntoConstraints = NO;  
35.     return newView;  
36. }  
37. - (NSMutableArray *) portraitConstraints:(UIView *)redView :(UIView *)greenView :(UIView *)blueView yellowView:(UIView *)yellowView orangeView:(UIView *)orangeView  
38. {  
39.     NSMutableArray *array = [NSMutableArray array];  
40.     // 注1：红色视图的宽度大于等于10 小于30    黄色视图的宽度大于40 小于120  水平  
41.     [array addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[redView(>=10,<=30)]-20-[greenView(>=40,<=120)]-20-[yellowView]-20-|" options:0 metrics:nil  
42.                                                                              views:NSDictionaryOfVariableBindings(redView, greenView, yellowView)]];  
43.     // 注2：垂直方向 red高度H:100<= <=160  蓝色 H:30<= <=60  橙色待定  
44.     [array addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-70-[redView(>=100,<=160)]-20-[blueView(>=30,<=60)]-[orangeView]-20-|" options:0 metrics:nil  
45.                                                                          views:NSDictionaryOfVariableBindings(redView, blueView, orangeView)]];  
46.     // 和注2类似  
47.     [array addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-70-[greenView(>=100,<=160)]-20-[blueView(>=30,<=60)]-[orangeView]-20-|" options:0 metrics:nil  
48.                                                                          views:NSDictionaryOfVariableBindings(greenView, blueView, orangeView)]];  
49.     // 和注2类似   或许有人会问 为什么得添加黄色和绿色，原因很简单，就是为了满足各个约束，避免造成约束不足  
50.     [array addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-70-[yellowView(>=100,<=160)]-20-[blueView(>=30,<=60)]-[orangeView]-20-|" options:0 metrics:nil  
51.                                                                          views:NSDictionaryOfVariableBindings(yellowView, blueView, orangeView )]];  
52.       
53.       
54.     // 注3：控制blued的宽度  
55.     [array addObjectsFromArray:[NSLayoutConstraint  
56.                                           constraintsWithVisualFormat:@"H:|-20-[blueView]-120-|" options:0 metrics:nil  
57.                                           views:NSDictionaryOfVariableBindings(blueView)]];  
58.     // 注4：为橙色高度添加约束条件  
59.     [array addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[blueView]-20-[orangeView(>=blueView)]-20-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(blueView, orangeView)]];  
60.       
61.     // 注4：为橙色添加宽度约束条件  
62.     [array addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[orangeView]-20-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(blueView, orangeView)]];  
63.     return array;  
64. }